“The transplantation is very close to the ‘cutting edge’, but it succeeded and the boy now has an immune system that has stabilised and can fight viral and bacterial infections,” said Ifversen.

As a result of the operation, he is expected to be able to manage for the rest of his life without any preventive medicines.

Making good use of redundant tissue
The operation on the boy was carried out in the UK using thymus tissue from a donor. There is often tissue left over when surgeons perform heart operations on babies because they have to remove some of it to get to the heart. Previously, this had usually been discarded.

The operation has worked so well that the boy’s immune defence is up to 75 percent capacity.

“We can see that the new thymus tissue has been taken over by the patient and has trained the immune system to recognise and not attack the boy’s own cells,” added Ifversen.

“That was the success criterion, because it would not be desirable if the thymus tissue trained the immune system to recognise the cells that had been transplanted from the child who had the heart operation.”

The prognosis is good
However, in reality, the long-term effects of the operation are unknown because nobody has tried living for 10-20 years with a transplanted thymus.

The Danish doctor, though, is optimistic. “Our experience is that his immune system has stabilised at a level that I feel will continue in the future,” said Ifversen.

The success of the operation may also prove in future to be a boon for cancer patients.

Ifversen points out that chemotherapy can be hard on thymus tissue and, in some cases, cause so much damage that the tissue loses its function. A transplant would then be a possible answer.